Grignard reagents are prepared by the reaction of magnesium metal with an organic halide. Grignard reagents have been prepared in the presence of ether solvents and tetrahydrofuran. It is known that the preparation of Grignard reagents are often quite difficult. Formation of these reagents is inhibited by the presence of water and alcohols, ethers and halides and by impurities on the surface of the magnesium turnings.
U.S. Pat. No. 2,552,676 relates to a method of manufacturing organometallic compounds. This process involves reacting organic halides with magnesium in the presence of glycol ethers. Alkyl Grignard reagents are described prepared from ethylene glycol diethyl ether, diethylene glycol diethyl ether, and tetraethylene glycol dimethyl ether. Aryl Grignard reagents are described which are prepared from ethylene glycol diethyl ether, ethylene glycol dimethyl ether, ethylene glycol n-butyl ethyl ether, diethylene glycol n-butyl ethyl ether, diethylene glycol diethyl ether, ethylene glycol, dibutyl ether, and tetraethylene glycol dimethyl ether.
U.S. Pat. No. 2,838,508 relates to a chemical process involving separating Grignard reagents from saturated or ethylenically unsaturated cyclic ethers. The process involves mixing a Grignard reagent, which is in the presence of tetrahydrofuran, with ethylene glycol or polyethylene glycol. The ethylene glycol or polyethylene glycol separates the tetrahydrofuran from the Grignard reagent and allows removal of tetrahydrofuran.
U.S. Pat. No. 3,758,620 relates to a process for preparing Grignard reagents. The process involves treating solvent systems such as ether solvents, diethyl ether, tetrahydrofuran, dibutyl ether and 1,2 dimethoxyethane with reducing halides. The addition of the hydride reduces and or eliminates the induction period which occur in most preparations of Grignard reagents.
It is desirable to have a solvent which may be used in the preparation of the Grignard reagent and not form precipitate upon cooling of the Grignard reaction. Further, it is desirable to have high boiling solvents used in the preparation of Grignard reagents.